Selective serotonin reuptake inhibitor
Selective serotonin reuptake inhibitors '(SSRIs) are the most popularly prescribed antidepressants they all work by selectively increasing the levels of serotonin in the body, especially the brain. Examples SSRIs include 'citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine and sertraline. Medical uses They are primarily used to treat depression, although they may also be used to treat anxiety disorders (including generalized anxiety disorder and obsessive-compulsive disorder). Side effects SSRIs are usually defined as agents with minimal affinity towards the , and -adrenergic receptors; although paroxetine does antagonize the mAChRs, weakly. Consequently they produces little of the side effects associated with the previous generation of antidepressants the . They usually have minimal effects on blood pressure, heart rate and metabolic parameters (like the levels and composition of fats and sugar in one's blood). Their principal side effects include: digestive complaints,Like constipation, diarrhoea, dry mouth, indigestion, nausea/vomiting, etc. Diarrhoea is more frequent with sertraline; digestive complaints, on average, are more frequent with fluvoxamine. orthostatic hypotension,Drops in blood pressure that occur upon standing up, leading, potentially, to dizziness and fainting. Far less problematic with the SSRIs than with the and psychiatric/neurologic side effects,Agitation, tremor, weakness, dizziness, anxiety and less commonly (occurring in fewer than 1% of patients taking them) worsening depression, suicidal thoughts and mania. These side effects are believed to be more frequent with fluoxetine than the other SSRIs. sleep changes,This includes difficulty falling and staying asleep (more common with sertraline and fluoxetine, especially fluoxetine), daytime drowsiness (more problematic with paroxetine), etc. Usually significantly less problematic than with the , , and . It is worth noting, however, that depression itself often causes sleep changes, hence any changes in sleep patterns could just be the antidepressants correcting this symptom. weight gain or loss,Weight changes are usually pretty minimal in people prescribed SSRIs, as opposed to TCAs and NaSSAs. Weight gain is more problematic with paroxetine; whereas weight loss is more frequent with fluoxetine. sexual dysfunction,Occurs in about 60%-70% of patients treated with them; includes impotence, loss of desire, inability/difficulty in achieving an orgasm, etc. More problematic with paroxetine, especially in females. sweating, muscle aches and rashes. Less common, yet serious side effects include: seizures, syndrome of inappropriate secretion of antidiuretic hormone (SIADH), bleeding problems, blood disorders and liver dysfunction. Citalopram and escitalopram may prolong the QT interval of the heart's electrical cycle, hence predisposing one to heart rhythm anomalies that may be fatal. Their dosage ranges are significantly more limited than are the other SSRIs, most likely due to the potential for this side effect. Escitalopram is believed to be less likely than citalopram to cause this side effect. Many physicians regularly monitor their patients that are prescribed these agents due to the potential for QT interval prolongation. Citalopram is also the most toxic of SSRIs in overdose, likely due to its potential for causing this side effect. Overdose Compared to other antidepressants, especially the previous generation of antidepressants the and they are comparatively non-toxic in cases of overdose. Of them citalopram and fluvoxamine are believed to be the most toxic in cases of overdose. Mechanism of action Properties Special populations Only fluoxetine and escitalopram (only approved for the treatment of adolescents over the age of 12, however) have been proven effective in treating children and/or adolescents; mostly because the others have not been sufficiently studied in well-designed clinical trials. They may be associated with a slighter higher risk of suicide in people under the age of 25 years. This potential danger was added to the labelling of every antidepressant in the United States (as a black box warning) and while one might expect that suicide rates would be on the decline in this population as a result, a recent observational study found that since the required this additional labelling, prescription rates have been on the decline (as one would expect, by up to 30%) while suicide rates in this population have been on the incline. In pregnant women the SSRIs are considered fairly safe, with regards to pregnancy outcomes, with the exception of paroxetine (which seems to increase the risk of congenital heart defects). Sertraline may be the best choice in this population as it crosses the placenta to the least extent. Untreated major depression, during pregnancy, is also associated with poorer pregnancy outcomes in itself, hence in some cases SSRIs may even improve pregnancy outcomes. See also * Atypical antidepressants * Monoamine oxidase inhibitors * Serotonin-noradrenaline reuptake inhibitors * Tricyclic antidepressants External links Notes Reference list Category:Antidepressants Category:Depression Category:Selective serotonin reuptake inhibitors